Thank you, but I did not mean to manually edit that, I just wanted to know whether there is some option somewhere to instruct Calibre about how to name folders. Thanks again.

When you chose to use Calibre, you handed off management to Calibre.

Those numbers are the internal {id} that links the metadata to the folder.
You might have 2 versions of the same book: 1 English, 1 French. Their title and author might be the same, but they will have different ID #'s (the tie breaker )